Lightning arrester



Patented Feb. 28, 1893.

LIGHTNING ARRESTER.

A; WURTS.

Ground,

nven for v WW a/zy' (No Model.)

Dynamo,

.THE NORRIS PETERS CO FHOTO LITHO.. WASNINGTON, D C.

. and shown certain forms of electrodes.

UNITED STATES PATENT OFFICE.

ALEXANDER WURTS, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THEWESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, OF SAME PLACE.

ARRESTER.

SPECIFICATION forming part of Letters Patent No. 492,548, dated February28, 1893.

Application filed March 12, 1892.

To all whom it may concern.-

Be it known that I, ALEXANDER WURTs, a citizen of the United States,residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in LightningArresters, (Case No. 489,) of which the following is a specification. 7T

The invention relates to certain improvements in the construction oflightning-arresters.

The object of the invention is to provide a lightning arrester whichwill afford a path for lightning discharges to earth, and which willautomatically operate to prevent the currents generated by dynamoelectric machines connected with the circuit, from continuing to flowacross the are established by the lightning discharge.

In certain other applications for patents filed by me, Serial Nos.413,749 and 413,082, I have described certain lightning arresters' inwhich the electrodes are composed of special materials which I havefound to have the characteristics of preventing the continuance of anelectric arc. Such metals I have for convenience termed non-arcingmetals. The principal metals which I have found to possess thesecharacteristics are zinc, antimony, cadmium, mercury and bismuth, andalso compounds of these metals with other metals, such, for instance, asa compound of zinc and copper, making a zinc brass, or a compound ofmercury with copper forming an amalgam, and likewise compounds ofcertain of these metals with each other, as for instance, zinc andantimony. I have discovered that electrodes made of these metals orcompounds when placed in close proximity to each other, afiord a readypath for lightning discharges; but possess certain properties whichprevent a dynamo current from continuing to flow across the interveningspace. In the applications referred to I have described the use andoperation of these metals In practice I find that it is desirable toplace the'electrodes in quite close proximity to each other, and it isalso desirable that the resistance offered to the passage of light-Serial No. 424,656. (No model.)

ning discharges should be as small as possible consistent with theprevention of the flow of the dynamo current. I have found thatcylindrical electrodes of the materials above referred to operate verysatisfactorily. I have also found that by corrugating 0r roughening thesurfaces of the cylindrical electrodes which are presented to eachother, the resistance offered to an electric charge, that is to say,What might be called the striking electromotive force, is considerablyreduced.

My present invention, therefore, relates particularly to theconstruction of electrodes of zinc, antimony, cadmium, mercury orbismuth or compounds thereof, or equivalent metals, the electrodeshaving confronting surfaces, presenting to each other numerous points orprojections. are advantageously made cylindrical, so that they may beturned upon their axes and thus new or fresh surfaces presented to eachother from time to time, yet they may be of other shape than cylindricalwithout departing from the spirit of the invention.

In the accompanying drawing, the figure is a plan of a lightningarrester embodying the features of the invention.

Referring to the figure, A A represent cylinders of non-arcing metals,such as hereinbcfore referred to. They are mounted upon a suitable baseB in any suitable manner. In the drawing they are shown as beingcylindrical in form, sides of the cylinders being presented to eachother. The distance which they are separated from each other may bevaried somewhat; but in practice I have found that they may be veryclose together, and still serve to interrupt the flow of current of veryhigh electromotive force. If the cylinders are smooth they will offer agiven resistance to an electric discharge, but by corrugating orroughening or knurling them, as indicated in the drawing, numerousprojections or points are presented by each cylinder to its adjacentcylinder or electrode, and this reduces the striking electromotive forceVery materially. The cylinders are mounted by \Vhile these electrodesmeans of screws 0 passing through suitable expose a fresh surface to theadjacent electrode.

In employing the lightning arrester one of the electrodes, for instance,the central one shown in the drawing, may be connected with the earth,and the outer ones with the respective sides of the circuit, a lightningdischarge will then escape from either side of the circuit to the earthacross the intervening air gap, but the dynamo current will be preventedfrom continuing to flow across this gap by reason of the effectsproduced by the non-arcing metal.

In practice I prefer to construct the electrodes with numerous smallpoints, as indicated, and to effect this the cylinders need be out onlyto a Very slight depth, and in this manner the points may be broughtinto very close proximity to each other and therefore a large number ofdischarge points are assembled.

I claim as my invention 1. A lightning arrester consisting of adjacentelectrodes of non-arcing metal having their surfaces milled, corrugatedor knurled and presentin gnumerous points to each other, substantiallyas described.

2. In a lightning arrester, the combination of cylindrical electrodeshaving rough, corrugated or knurled surfaces presented to each other,said electrodes being composed of non arcing metal, such as zinc orantimony or their equivalent.

3. In a lightning arrester, electrodes cylindrical in form having theirsides adjacent to each other and having their surfaces studded withnumerous points and means for turning one or more of said cylindricalelectrodes upon their axes for presenting fresh surfaces,

ALEXANDER WURTSL Witnesses:

JAMES W. SMITH,

lHARLns A. TERRY.

